Mrs. Krabappel takes Bart's class on a trip to the Springfield Nuclear Power Plant. While riding through the plant in an electric cart in an effort to find them, Homer takes his eyes off his driving and crashes into a radioactive pipe, causing the plant to shut down.
Homer is fired for repeated safety violations. Depressed and unable to find a new job, he writes a good-bye note and leaves to jump off a bridge. Lisa finds the note and alerts the family. Rushing across the bridge to stop him, they are almost run down by a speeding truck. Homer pulls them out of the way just in time.
Homer embarks on a public safety crusade to make Springfield a safer place to live. Speed bumps, warning signs, and public awareness posters are placed throughout the city. When he becomes bored with traffic safety, Homer takes on the nuclear power plant, rallying the people of Springfield to his cause. To end the furor Homer is creating, Mr. Burns offers him a position as a safety supervisor with a large pay increase. Homer accepts the job, telling the mob to go home and assuring them that he will make their nuclear power plant safe.
